1. Field of the Invention
The present invention relates to an input device that includes an actuator equipped with a mobile part that faces fixed magnets and moves in relation to the fixed magnets.
2. Description of the Related Art
In recent years, devices equipped with actuators have been developed as user interfaces having feedback functions for users. Japanese Unexamined Patent Publication No. 2000-330688 (hereinafter referred to Prior Art 1) discloses an information receiving apparatus as an example having an actuator in which coils are arranged as opposed to magnets arranged in a flat state. In this apparatus, current to be supplied to the coils is controlled so as to move the coils in relation to the magnets. Accordingly, it is possible to stimulate users' sense of touch by controlling the actuator.
In a case where the actuator is incorporated into a mouse that is normally used for personal computers, it is possible to transmit various forms of information to users from a computer via the mouse. For instance, click points can be made recognizable through vibration, or users can feel as if they were actually shooting a gun or an arrow in a computer game or the like. In other words, a conventional mouse can be utilized as a man-machine interface.
However, the function of feeding information back to a user through his/her sense of touch is not valid unless the user is touching the actuator. Driving the actuator when the user is not touching it leads to waste of power, and the life of the actuator as the driving unit is shortened wastefully.
In the invention disclosed in Prior Art 1, light receiving elements are arranged on the surface of the actuator, so that a touch detector can be activated when a finger is placed on the light receiving elements. In this prior art, an operation is stopped in accordance with a signal notifying that a finger has already been removed from the light receiving elements. Thus, waste of power is prevented when a user is not touching the actuator, and shortening of the life of the actuator can be avoided (specifically shown in FIG. 5 of Prior Art 1).
In a case where the above actuator is incorporated into a conventional mouse or the like, however, it is necessary to maintain a space to accommodate magnets and coils. With this actuator, the number of components is increased, and the entire structure is further complicated, resulting in difficulty in assembling. Also, other problems, such as increase of production costs, are caused. In a case of incorporating a touch detector utilizing light receiving elements, the above problems are even more serious.